In the championship rounds, the two fighters came alive and a tenth round was punctuated by numerous defiant Golovkin shots to the head that seemed to have Canelo rocked and sway the action in favor of the older man.
While Golovkin was widely believed to have been unlucky not to win their first encounter a year ago, there was no controversy about Saturday's outcome.
Golovkin told reporters afterwards: "I'm not going to say who won tonight, because the victory belongs to Canelo according to the judges".
The Las Vegas fight came almost a year to the day since a split-decision draw left the Kazakh boxer stunned.
Speaking at a media conference later in the night, Golovkin congratulated Canelo on this win and elaborated on his disappointment. He's a very good fighter. In fact, you can already place odds on who you think would win Alvarez-GGG 3.
A great boxing fight was just ruined by a bogus decision by the judges ... again.
"We knew the best way to beat him was to make him go backwards", Alvarez said. He was the one who was backing up. The fight was extremely close, and of course, the decision was a controversial one.
And asked on whether or not there will be a rematch, he said: "If the people want another fight then we'll do it again". I promised the people I would go for a knockout. "It was a clear victory".
The build-up to the contest had featured accusations by the fighter from Kazakhstan that Alvarez was covered in injection marks during their first fight, which took place at the same T-Mobile Arena venue.
Olympic medallist and unbeaten professional boxer Michael Conlan reckons that Canelo deserved to win.
Alvarez and Golovkin are due to make their entrances to the ring from around 4am United Kingdom time. Great fight, but GGG can feel that decision should have gone his way.